Kew York Agricultural Expeuimbxt Station. 233 



represent the consensus of opinion among scientific men at the 

 present time, current popular thought has been thrown more or 

 less into confusion on these points by recent newspaper discus- 

 sions over the substitution of soda for potash in feeding plants. 

 This discussion was started and largely maintained by the late 

 Andrew H. Ward and. aided by the press, he so persistently 

 exploited his belief in the possibility of this substitution to the 

 advantage of the farmer that he made more or less impression 

 upon the views of the agricultural public. This writer wa« a'ble 

 to present little or no experimental proof of his position, his 

 arguments being largely assertions. In view of the situation it 

 was thought wise to institute experiments touching thie matter, 

 not because of anything new in the scientific evidence advanced 

 which should cause the question to be reopened, but rather to be 

 able to throw into the argument more experimental data of 

 recent origin. It is desirable before presenting the plan of these 

 experiments and the results obtained, to review somewha.t briefly 

 the evidence furnished by past investigations, without attempt- 

 ing, however, to compile a monograph on the subject. 



RESULTS OF PREVIOUS INVESTIGATIONS. 



W. Knop^ concluded in regard to the growth of maize that in 

 the first period of growth the plant may get along without soda, 

 yet for the full development of the plant, soda must be added to 

 the plant food. 



HellriegeP studied the potash need of barley, using " quartz 

 sand almost potash-free," and potash salts in quantities from 

 to 282 parts per million of soil. He found that 47 parts per 

 million was sufficient for the maximum growth. The use of 

 larger amounts of potash did not seem to cawse a greater yield, 

 but the potash was taken up by the straw in larger proportions. 



Nobbe, Schroeder and Erdman^ found that in a nutritive solu- 



' Abstracted in Jahrh. f. Agr. Cliem., 4 : 127. 

 ^Abstracted in JaJirb. f. Agr. Cliem., 10 : 117. 



^Laudic. Vers. Stat., 13 : 321 and 401, abstracted in JaJiri. f Agr. Cliem., 

 14 : 104. 



